Hi,
I am writing this on behalf of a friend of mine who does not have access to the Internet at the moment, who has been having problems with fluctuating PH Levels.
His reef tank is a Aqua One Windsor 66 Corner Aquarium,
Water Volume 190 Litres - Displacement for 25 kgs of Live Rock No Sump Fitted
Uses Weipro Protein Skimmer which he has recently upgraded.

The tank has been running for 3 years now with no major problems, apart from Nitrate and now PH Problems.

The PH Levels have started to fluctuate over the last 3 months from 8.0 in the daytime (2.00 p.m.) to 7.6 at night (10.00 p.m.) to yesterday's levels of 7.6 in the daytime (2.00 p.m.) to 7.3 at night (10.00 p.m.)
PH has been tested using 2 different test kits but still getting same results.

His tank parameters are as follows:-
Salinity 1.025
Temp 26.5 Degrees
Nitrate 40-50 (Used to be 10)
Alkalinity 9
Magnesium 1380
Calcium 380-400
Salt Used TMC Standard Salt
Water Changes 20 Litres every 3 weeks
External Filter with Activated Carbon, Rowaphos, Purigen & Seachem Matrix.
Lighting 1x150w Metal Halide with 2x24w Actinic T5 Tubes. (Halide on for 6 hours, T5's on for 2 Hours either side of halide)
Powerheads: 1 Vortech MP20 & 1 Koralia 4
Feeding: Fish Flake & 1 cube of Frozen Mysis per day.
Coral Feeding: Zooton & Gamma Nutreplus twice a week.

His corals and fish are all O.K. but he is getting concerned about the PH Levels falling and the Nitrate Levels rising.
He has tried powdered PH buffers but they do not seem to make any difference.
Any help would be appreciated.
Thanks
Adrian
Reefkeeper64

I would say without a sump he should up his water changes to 10% a week this should help with the nitrates.

How much surface water movement is there as this helps with gas exchange and in turn will help with maintaining ph

Hi Dave,
There is a lot of water movement at the top of the tank, he has considered adding any airstone to the the rear of tank to aid the gas exchange, he has just checked the PH again tonight and it is down to 7.2 when the lights have gone off.
I cannot understand why it keeps falling.
Thanks
Adrian

What make test kits is he using?
are you sure the kh is 9, I would have thought at that level it would provide a buffering capacity.
Is it possible to draw air into the skimmer from outside, is the room the tank is in well ventilated

Hi Dave,
He is using Salifert and API Test Kits and gets the same results for both PH and Nitrates.
Unfortunately he cannot draw air from outside for the skimmer as the tank is situated in a corner of a room not near any windows.
Regards
Adrian

Hi m8 ,have a look at the article on ph under simons Reef eden on here ,Chasing the tail of PH.

Thanks Lindsay, will print it out for my friend and let you know what happens.
Regards
Adrian

Cool m8 .

Is your mate using Tropic marin standard salt with RO water?

Tom

Hi Tommo,
Yes, he uses RO water put through a DI unit, it has a TDS of 0.
Regards
Adrian